Such a system is already known from the international patent application WO 83/02209 published under the Patent Cooperation Treaty. Therein each of said data packets is simultaneously transmitted from one module to all the modules to be loaded. But each of these modules has previously been so conditioned that it is only able to accept predetermined ones of these data packets. Such a conditioning operation has to be individually performed for each module and is therefore time consuming. This time may be relatively high in accordance with the number of terminal modules, as is the case for instance in an automatic telecommunication switching system with distributed processor control such as described in various articles published in Electrical Communication, Volume 56, No 2/3, 1981, and particularly on pp. 135 to 160 and 173 to 183.